[Discrete probability of a model for information provision on early embryonic development].

A percolation model of the diffuse redistribution of morphogenetic information in early regulative development is analyzed. It is demonstrated that the statistical average values of cell connectedness remaining below the percolation threshold of the spatial redistribution of developmental determinants do not provide for the formation of cell structures of the necessary size. The average number of cell interactions should exceed the percolation threshold, and, therefore, the carriers of morphogenetic information in early development can move over distances comparable with the size of the entire embryo.

[Relation of cyclic and noncyclic electron transport in Rhodospirillum rubrum chromatophores. I. Experimental study of the kinetic characteristics of dark reduction of P870 with different donor concentrations in the medium].

The kinetics of the dark recovery of photo-oxidized bacteriochlorophyll P870 was studied as a function of the intensity and duration of actinic light illumination at different concentrations of a donor in the medium. From the comparison of the experimental data with the results of mathematical modelling of the processes under investigation [1] it is concluded that electron transport is triggered for another pathway, whenever the concentration of the donor in the medium attains a certain critical level.

[Theoretical study of the kinetics of dark reduction of photochemically oxidized bacteriochlorophyll in the reaction center of Rhodospirillum rubrum chromatophores].

It is shown from the results of theoretical study that the scheme involving two successive interacting components of the pool of secondary acceptors shows the biexponential character of the kinetics of dark reduction of the pigment of P870 observed in the experiment. The velocity constants of the electron transport reactions considered are evaluated.